Problem: Is ${816852}$ divisible by $4$ ?
Solution: A number is divisible by $4$ if the last two digits are divisible by $4$ . [ Why? We can rewrite the number as a multiple of $100$ plus the last two digits: $ \gray{8168} {52} = \gray{8168} \gray{00} + {52} $ Because $816800$ is a multiple of $100$ , it is also a multiple of $4$ So as long as the value of the last two digits, ${52}$ , is divisible by $4$ , the original number must also be divisible by $4$ Is the value of the last two digits, $52$ , divisible by $4$ Yes, ${52 \div 4 = 13}$, so $816852$ must also be divisible by $4$.